Add creme de menthe, creme de cacao, and food coloring (if you're using it) to the cooled marshmallow mixture. Stir until combined.
In a separate large mixing bowl, add remaining whipping cream (1-⅓ cup). Beat until stiff (like whipped cream!)
Add whipped cream to the marshmallow mixture. Gently fold in.
Pour filling into prepared crust. Spread smooth.
Sprinkle extra cookie crumbs on top.
Place pie in the freezer. Freeze until very firm, at least 2 hours.
To serve: Remove from freezer 5-10 minutes before slicing.
If your creme de menthe liqueur is clear, add a couple drops of green food coloring to make it festively green! For extra minty flavor, use mint Oreos in your Oreo crust. Or, since it's "that time of year," you can use Thin mints too!